One is imaginary, the other is made up. There's a huge difference.<br /><br />Edit: Okay, time for a serious answer though, if you believe that.<br /><br />Lucifer was a fallen angel. His name in Latin is synonymous with "illumination", because his sin was questioning God in his hunt for knowledge. He was cast out, to live in torment forever in Hell. The story goes that he continues to hate God and plots revenge, and exercises his remaining power as a fallen angel to tempt and corrupt people. <br /><br />The antichrist is a person, usually depicted as a man. He'll supposedly be a very charismatic leader. He'll be so popular, in fact, he'll unite the world under a single utopian government... and then lead everyone to eternal sin, to ensure they all go to Hell.